Soft-bore monoblock pouring tube

Abstract

A refractory pouring-assembly component is disclosed for use in the continuous casting of molten metals, especially steel. The invention is described as reducing thermal shock-induced cracking, including both radial and horizontal cracks. The component comprises a copressed plate and depending pour tube having a bore. The surface of the plate is made from a scratch-resistant refractory material and the pour tube is made from a thermal shock-resistant refractory material. The pour tube extends through and is substantially coplanar with the plate, so that the molten metal sees a joint-free, thermal shock-resistant material throughout the entire length of the bore.

I claim: 
     
       1. A refractory pouring assembly for the continuous casting of molten metals comprising: (a) an elongated body having an inner surface defining a bore, the body comprising a thermal shock-resistant refractory material, the body having a first end and a second end; and   (b) a plate having a smooth, flat surface surrounding the first end of the body, the surface substantially coplanar with the first end of the body, the surface comprised of a scratch-resistant refractory material, and the plate having been copressed with the body.   
     
     
       2. The assembly of claim 1 wherein the body and the plate comprise a joint-free, one-piece composite member. 
     
     
       3. The assembly of claim 1 wherein the assembly is isostatically pressed. 
     
     
       4. The assembly of claim 1 wherein the scratch-resistant refractory material is at least 10 mm thick. 
     
     
       5. The assembly of claim 1 wherein the surface of the plate defines an annulus around the bore of the body and the annulus has a width of at least 10 mm. 
     
     
       6. The assembly of claim 1 wherein the thermal shock-resistant material has a thermal expansion coefficient below about 6×10 -6  /° C. 
     
     
       7. The assembly of claim 1 wherein the thermal shock-resistant material is alumina graphite comprising between about 50 to about 80 weight percent alumina and between about 20 to 50 weight percent graphite. 
     
     
       8. The assembly of claim 1 wherein the scratch-resistant refractory material has a room temperature modulus of rupture above about 2500 MN/m 2 . 
     
     
       9. The assembly of claim 1 wherein the scratch-resistant refractory material comprises at least about 50 weight percent alumina. 
     
     
       10. A refractory pouring assembly for the continuous casting of molten metals wherein the assembly is part of a tube exchange mechanism having a tube plate and an upper fixed plate, the assembly comprising: (a) an elongated body having an inner surface defining a bore, the body comprising a thermal shock-resistant refractory material, the body having a first end and a second end; and   (b) a plate having a smooth, flat surface surrounding the first end of the body, the surface substantially coplanar with the first end of the body, the surface comprised of a scratch-resistant refractory material, and the plate having been copressed with the body.   
     
     
       11. The assembly of claim 10 wherein the plate comprises the tube plate and the second end of the body extends into a casting mold. 
     
     
       12. The assembly of claim 10 wherein the plate comprises the upper fixed plate and the second end of the body extends into a metallurgical vessel. 
     
     
       13. A refractory assembly for use in the continuous casting of molten metals, the assembly comprising: (a) an elongated body having an inner surface defining a first bore, the body having a top end and a bottom end;   (b) an annulus defining a second bore, the annulus fixedly attached to the top end of the body so that the first bore and the second bore are aligned, the annulus comprising a thermal shock-resistant refractory material; and   (c) a plate having a smooth, flat surface surrounding and coplanar with the annulus, the surface comprising a scratch-resistant refractory material, and the plate surface having been copressed with the body and the annulus.   
     
     
       14. The assembly of claim 13, wherein the assembly is used in a tube exchange mechanism having a tube plate and an upper fixed plate. 
     
     
       15. The assembly of claim 14, wherein the plate comprises the tube plate and the bottom end of the body extends into a casting mold. 
     
     
       16. The assembly of claim 14, wherein the plate comprises the upper fixed plate and the bottom end of the body extends into a metallurgical vessel.